Easiest way to create a signature fascimile on an Android tablet

I would like to create a **fascimile of my signature. Ideally, a high resolution png with a transparent background**. At my disposal is an Android tablet with a stylus (Samsung Galaxy Tab S9+) and a Linux (Ubuntu) laptop for post-production if necessary. I would prefer to avoid using online services and keep the signature on my devices. How do I go about it? Starting with the drawing app for Android. If practical, one that is open source and in F-Droid would be best.